x y z are real numbers so that 20x^2+18y^2+5z^2-24xy+12yz+4xz = 0 a : b : c= x : y : z where a b c are integers and gcd |a|,|b|,|c| =1 find value of a^2+b^2+c^2

The salesperson earns a 5% commission on the first $5,000 she has in sales. the salesperson earns a 7.5% commission on the amount of her sales that are greater than $5,000. this month the sales person had $8,000 in sales. what amount of commission, in dollars, did she earn?